Automatic meter reading (AMR) systems are generally known in the art. Utility companies, for example, use AMR systems to read and monitor customer meters remotely, typically using radio frequency (RF) communication. AMR systems are favored by utility companies and others who use them because they increase the efficiency and accuracy of collecting readings and managing customer billing. For example, utilizing an AMR system for the monthly reading of residential gas, electric, or water meters eliminates the need for a utility employee to physically enter each residence or business where a meter is located to transcribe a meter reading by hand.
There are several different ways in which current AMR systems are configured. In a fixed network, endpoint devices at meter locations communicate with readers that collect readings and data using RF communication. There may be multiple fixed intermediate readers located throughout a larger geographic area on utility poles, for example, with each endpoint device associated with a particular reader and each reader in turn communicating with a central system. Other fixed systems utilize only one central reader with which all endpoint devices communicate. In a mobile environment, a handheld or otherwise mobile reader with RF communication capabilities is used to collect data from endpoint devices as the mobile reader is moved from place to place.
AMR systems that are currently available are generally one-way, one-and-a-half-way, or two-way systems. In a one-way system, an endpoint device periodically turns on, or “bubbles up,” to send data to a receiver. One-and-a-half-way describes systems in which a receiver sends a wake-up signal to an endpoint device, which in turn responds with a reading. Two-way systems enable command and control between the endpoint device and a receiver/transmitter.
U.S. Pat. No. 5,918,380 to Schleich et al., for example, discloses a metering system for metering the consumption of electrical energy that includes an encoder device for transmitting a RF signal and a receiver device for receiving the radio frequency signal transmitted by the encoder device. The encoder device periodically generates an encoded RF signal for transmission and the receiver device has a decoder for decoding the encoded RF signal received from the encoder device.
U.S. Pat. No. 5,914,673 to Jennings et al. relates to an AMR system of the type used for reading utility meters by using a fixed RF network. The system disclosed by Jennings et al. is a network comprised of multiple cells, with each cell containing a single data concentrator unit and a typically large number of meter interface units. In operation, each meter interface unit is assigned a unique time displacement number and responds to a meter reading request from a data concentrator unit based upon its time displacement number.
While one-way and one-and-a-half-way systems provide many advantages over manual read meters, they do not fully enable two-way communication between receivers and endpoint devices. As the demands of energy metering increase, additional functionality requirements will drive new technological solutions.
For example, it is desirable for a utility to be able to reset a meter after collecting the meter's demand reading. A demand value is the highest, or peak, power demand over a unit of time. Systems currently available allow a demand reset to be calendar scheduled, but this approach disconnects the demand reset from the meter read and results in a mismatch of timestamps that is not favored by utilities. In these systems, recognition of the reset event is not provided proof-positive to the meter reader and inference rules must be applied. This impacts the business rules of many utilities and is not desirable. Other systems may allow a demand reset command to be sent to an endpoint device but do not provide any confirmation that the command was received and executed, resulting in erroneous readings and, ultimately, an unreliable system.
Further, while the demand is generally monitored by a utility on a monthly basis, it is frequently desirable to be able to archive the demand value, or other interval data, for a period of time, perhaps two or three months. This requires the endpoint devices and readers to have increased data storage and transfer capabilities that are not available in current AMR systems. Further, proof positive demand reset coupled with a reading of the demand information from an endpoint device is usually accomplished through a physical interface with the endpoint device in AMR systems that are currently available.
There is, therefore, a need for an AMR system that addresses the data collection shortcomings described above.